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Academic literature on the topic 'Sénescence reproductive'
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Journal articles on the topic "Sénescence reproductive"
Combe, Laurette, and Abraham J. Escobar-Gutiérrez. "Sénescence d’un pied de maïs : évolution de la floraison à la récolte." Botany 87, no. 11 (November 2009): 1036–53. http://dx.doi.org/10.1139/b09-066.
Full textDissertations / Theses on the topic "Sénescence reproductive"
Pineaux, Maxime. "Gènes immunitaires du CMH chez un oiseau monogame : fitness et stratégies de reproduction." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30275.
Full textParents are expected to adjust their reproductive decisions depending on the future advantages they will gain. These advantages include increased offspring fitness through acquisition of genetic benefits from mates. However, constraints may force individuals to mate with suboptimal partners. The costs of suboptimal pairing should have created selective pressures inducing the evolution of counter strategies. In this thesis, I investigated whether individuals adjust some reproductive post-pairing decisions depending on the prospective genetic characteristics of their offspring, along with the fitness consequences of these genetic characteristics, using a monogamous seabird species, the black-legged kittiwake (Rissa tridactyla). First, I found that chick functional diversity at major histocompatibility complex class II (MHC-II) genes, which play a pivotal role in vertebrate immunity, was positively associated with fitness-related traits in females, but not in males. Accordingly, parents with functionally similar MHC-II, that were more likely to produce chicks with low MHC-II-diversity, overproduced sons, in line with sex allocation theory expectations. Second, I report experimental evidence that genome-wide genetic similarity between mates decreased egg hatchability when the fertilizing sperm was old. In line with our expectations, genetically-similar pairs performed behaviors allowing avoidance of fertilization by old sperm. Overall, this thesis provides evidence that parents flexibly adapt some reproductive decisions in response to within-pair genetic similarity at key functional genes and over the whole genome, thereby partly compensating the detrimental consequences of suboptimal pairing
Meunier, Léna. "Reproductive biology and senescence impact on postcopulatory sexual selection in a wild polyandrous bird, the North African Houbara Bustard (Chlamydotis undulata undulata)." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCK028.
Full textPolyandry, when females mate with multiple males, increases the opportunity for sexual selection to operate, because in addition to competition between males for access to the female (pre-copulatory sexual selection), sperm from different males also compete for fertilization (post-copulatory sexual selection). This often results in most offspring being sired by the last male, a phenomenon called last male precedence (LMP). In addition to mating order, sperm quantity and quality can also influence the outcome of sperm competition. As males age, sperm quality and quantity decrease, resulting in reduced reproductive success. In the North African Houbara Bustard (Chlamydotis undulata undulata), females are polyandrous, and males suffer from reproductive senescence. The thesis aims at improving our understanding of the reproductive biology of houbara bustards, reproductive senescence and its impact on male reproductive success and post-copulatory selection.In the first part, to improve the knowledge of the species’ physiology of reproduction and to construct a solid base for houbara reproductive anatomy and sperm morphology and later storage mechanism in the female tract, we explored anatomy and histology of the female and male reproductive systems during and out of the breeding season and sperm morphology was described. In the second part, we investigated the underlying mechanisms of LMP and the storage dynamics within the oviduct during competitive inseminations. In the third part, we investigated male reproductive senescence and its relationship with post-copulatory selection. This work was divided into four sections to investigate different aspects of reproductive ageing. Firstly, we examined seasonal testosterone levels and a possible age-related pattern. Second, we investigated a possible trade-off between sperm number and quality across ages. Thirdly, to test male age, sperm age, and their possible interaction on sperm quality and reproductive success, sperm ageing in the male tract was investigated by controlling the timing of collection intervals for young and old males. Finally, LMP was studied under controlled experimental conditions to disentangle the effects of male age, mating order, and sperm quality on siring success.This thesis presents the first description of houbara reproductive anatomy and histology and sperm morphology classification. Active sperm displacement is likely to be the main mechanism of LMP. There was no evidence of an age-related pattern of testosterone levels throughout the breeding season. Peak testosterone levels preceded peaks in sexual behaviour and sperm characteristics. We found a positive covariation between sperm quantity and several sperm quality traits, and male age did not influence the strength of this covariation. No evidence of sperm ageing during prolonged storage in the male tract was observed. On the contrary, sperm collected at longer intervals had higher quality, which was reflected in higher hatching success. Consistent with previous work, older males had lower sperm number, volume, motility and velocity and sired offspring with impaired growth rate. Finally, we found no evidence of an age effect on LMP. Regardless of age, sperm from the last male in the insemination sequence sired approximately 60% of the offspring. Overall, this work has provided a better understanding and new insights into the reproductive biology of houbara bustards and the mechanisms of post copulatory selection
Crosland, Agathe. "Lien entre la croissance et les sénescences reproductive, actuarielle et immunitaire chez un insecte." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCK006.
Full textSenescence, the decline in the performance of the organism with age, is an almost universal and therefore a very familiar phenomenon. However, the “why” and “how” of this phenomenon have only recently begun to be elucidated. From an evolutionary perspective (the “why”), the decline in the strength of natural selection with age creates an opposition between performance early and later in life, generally to the detriment of the late period. The disposable soma theory, in particular, proposes that the decline of the organism comes from the accumulation of damage, poorly repaired, because resources are allocated to advantageous functions earlier in life, such as reproduction or growth. If the link between reproduction and senescence has been extensively studied over the last century, knowledge on the relationship between growth and senescence remains to be consolidated.In this thesis, we tested the effect of the growth rate on three aspects of senescence: reproduction, survival and immunity, in the mealworm beetle, Tenebrio molitor (Coleoptera, Tenebrionidae). We used two complementary approaches, one based on the manipulation of growth rate by the larval environment and the second based on the study of inbred lines, thus addressing the genetic component of the link between growth and senescence.These approaches have all shown that a stronger investment in growth accelerates the reproductive senescence. The phenotypic approach did not show any cost of a high growth rate on longevity, while antagonistic genetic correlations were highlighted. Finally, manipulating growth rates influences which type of immune defense is favored by insects. Our results therefore show that growth rate has a variable effect depending on the senescence parameters considered
Pardo, Deborah. "Démographie, sénescence et changements globaux chez deux espèces extrêmement longévives." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00750625.
Full textAubry, Lise Myriam. "Influence du recrutement sur les variations des paramètres démographiques avec l'âge et la vitesse de sénescence chez la mouette tridactyle, Rissa tridactyla." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/1581/.
Full textI used a 30-year study of long-lived seabirds (black-legged Kittiwakes) that breed in Brittany to study the evolution of trade-offs between early-life breeding decisions, future reproduction, and survival. I first found that recruitment age and habitat selection were intimately linked. Recruitment age further influenced breeding success and survival trajectories. Furthermore, sources of observed (reproductive covariates, experience) and unobserved heterogeneity (frailty) explained substantial amounts of variability in breeding success and survival. Overall, intermediate age recruits (age 5) seemed to maintain high breeding success over life and minimized senescence in survival compared to other recruits. Even though individual fitness showed that earlier recruitment was the most beneficial recruitment strategy, the costs associated to delayed recruitment seemed minimal
Lecomte, Vincent. "La Sénescence en milieu naturel : une étude pluridisciplinaire chez deux oiseaux marins longétifs, le grand Albatros et le Pétrel des neiges." Poitiers, 2010. http://theses.edel.univ-poitiers.fr/theses/2010/Lecomte-Vincent/2010-Lecomte-Vincent-These.pdf.
Full textVery little is known on the deterioration of physiological and behavioural performances with age in wild animals. Given the multifaceted nature of senescence, identifying the effects of age on physiology and behaviour remains a challenging. We investigated the effects of age on a broad array of phenotypic traits in two long-lived seabirds, the Wandering Albatross Diomedea exulans (age 2–48+ years; Ile de la Possession, Southern Indian Ocean) and the Snow Petrel Pagodroma nivea (age 7–46 years; Terre Adélie, Antarctica). We studied foraging behaviour using satellite tracking and miniaturized activity loggers, and monitored reproductive performance. An array of phenotypic traits (immune function, levels of oxidative stress, antioxidant defenses, baseline hormonal levels, endocrine and cardiac stress responses) known to reflect senescence in vertebrates was also examined. In Wandering albatrosses, there was age related patterns in foraging behaviour, stress response and reproductive performance, but not in baseline physiology. There was an unexpected pattern of spatial segregation by age in the foraging areas of male albatrosses. Old males, but not females, travelled a greater distance but were less active at the sea surface, and exhibited low foraging efficiency, suggesting that foraging ability (i. E. The ability of individuals to extract energy from their environment) might play a central role in shaping ageing patterns in natural conditions. Moreover, the stress response of non-breeding males, but not breeding males, was affected by age, suggesting that age-related patterns are enhanced when individuals face ‘challenging’ conditions. In contrast, there was no detectable effect of age in females, suggesting that senescence rates are sex-specific in wild seabirds, as in humans an in laboratory model animals. In Snow Petrels, there was no detectable effect of age on PHA-induced immune response, PHA-induced hormone levels, chick growth or chick physiology, suggesting that physiological senescence is difficult to detect in this very long-lived seabird. Overall, our results highlight that age, gender, reproductive status and foraging ability interact in shaping ageing patterns in natural conditions, and suggest that long-lived seabirds maintain a high level of physiological fitness in old age, which supports the disposable soma theory
White, Joël. "Stratégies d'accouplement et conflits sexuels dans un contexte monogame : le cas de la mouette tridactyle Rissa tridactyla." Paris 6, 2007. http://www.theses.fr/2007PA066524.
Full textDurollet, Marie. "Régulation de la fonction cardio-respiratoire au cours du cycle de vie de Nothobranchius furzeri : rôle de la température." Thesis, La Rochelle, 2015. http://www.theses.fr/2015LAROS037/document.
Full textCardio-respiratory system plays a key role in an organism by delivering oxygen and nutrients towards the cells. Exploring its age-dependant changes is therefore a corner stone for assessing the organism capacity to meet its energetic needs along its life cycle, and for the understanding of mechanisms involved in the mortality due to aging process. This study was realized in a vertebrate with an extremely short lifespan (~6 months), the fish Nothobranchius furzeri. Temperature is an external factor that regulates longevity. Here, fish were acclimatized at two temperatures, 26 °C considered as the optimal temperature for this species, and 22 °C. Biological responses of fish were evaluated at individual level through the assessment of aerobic metabolic scope (AS), growth, reproduction, locomotion and digestion, which are considered to be relevant indirect measurement of fitness. Furthermore, mechanisms involved in the cardiac function regulation were explored through a morpho-functional study of cardiomyocytes. Along the individual life cycle, two phases were emphasized: 1) the first corresponds to AS elevation from the juvenile to the adult stages, following by 2) a second phase reflecting the entrance in the senescent stage, characterized by the decline in AS, cardiac performances and in activity level. A temperature reduction increases the individual longevity and slows-down deleterious effect of aging on both AS and cardiac function. This study will contribute to provide a global vision of senescent effects on cardio-respiratory system, and a better understanding of the mechanisms involved in temperature-dependent increase in longevity